Carvin Active Bass - Pull Out Knob to Save the Battery?

The title pretty much says it all. Does anybody know if I can avoid pulling the cable out of my Carvin active bass to save the battery by pulling out the volume knob, thereby switching the bass to passive mode?

I guess I can just leave the knob pulled out for a few days with the cord plugged in, but I thought I'd try to save myself two batteries by asking here first.

Typically the preamps that have active/passive options like this remain on even when you switch to passive mode. Many reasons for this, but a big one is that it keeps the bass from popping very loudly when you go back to active mode. Also, the on/off mechanism is tied to the cable being inserted, and not the position of the A/P switch.

TalkBassFriendly Advertisement

You can use a 3PDT mini toggle switch for active/passive switching that disconnects the battery, but there may be loud pops when switching, as the preamp powers on.

This is really quite absurd, however, considering that the average current draw of a preamp is extremely insignificant, compared with the capacity of the average 9V battery. If your batteries are not lasting at least a year, something is miswired.

I was getting scratchy noises from the instrument jack of my SB5K, so I unscrewed the jack plate to spray some Deoxit on the contacts. The switch that turns on the pre's batteries is visible: two tabs of metal, normally not in contact. When you insert a guitar plug, the tip pushes one of the metal tabs into the other.

Pulling the knob on a Carvin preamp bypasses it, but does not turn off power.

Why is it such a big deal to unplug?

Re battery life, my preferred 9V battery is the Ultralife lithium. Widely available for smoke detectors, they last for-freakin'-ever in preamp duty. Shelf life for batteries still in the package is rated at 10 years, but IME is even longer. Compare that to maybe 4 years at best from alkalines.

Using the switch while the bass is "in use" CAN damage your amplifier.
It might cause a very loud plop signal.

If you really only use the switch when the amp is on standby, it is no problem. But Murphy's law says, that you will forget the put the gain of the amp to zero or on standby somewhen. And this will happen at the worst moment ...

The amp needn't be damaged and you can put in such a switch.
But we would nor recommend it ...

The only time its hard to unplug for me is when I'm on a church gig and the set in split up with music at the beginning and ending. Since its all quiet and the bass is plugged into the PA, I can't just yank the cable out in the middle of the service, so I end up having to leave it plugged in. I wish there were a way to stop the battery drain at that point. But its only 45min to an hour usually.

Would be nice to be able to leave it plugged in on 4 hour gigs during the breaks as well.

Just leave it plugged in. The batteries last a long time! I'm a music teacher and lately I've been leaving mine plugged in all day without any issues. I've been doing that know for several weeks and the batteries are fine.

The only time its hard to unplug for me is when I'm on a church gig and the set in split up with music at the beginning and ending. Since its all quiet and the bass is plugged into the PA, I can't just yank the cable out in the middle of the service, so I end up having to leave it plugged in. I wish there were a way to stop the battery drain at that point. But its only 45min to an hour usually.

Would be nice to be able to leave it plugged in on 4 hour gigs during the breaks as well.

Click to expand...

You don't have to unplug it during a gig. I never do. But at home when you aren't playing, just pull the plug. Sometimes I forget and leave my bass plugged in for days at a time though.

You can also get one of those silent plugs that have a switch on them. When you pull the plug out of the bass it mutes your signal and you don't hear a pop.

The only time its hard to unplug for me is when I'm on a church gig and the set in split up with music at the beginning and ending. Since its all quiet and the bass is plugged into the PA, I can't just yank the cable out in the middle of the service, so I end up having to leave it plugged in. I wish there were a way to stop the battery drain at that point. But its only 45min to an hour usually.

Would be nice to be able to leave it plugged in on 4 hour gigs during the breaks as well.

Click to expand...

I play in church. I leave mine plugged in from 8 till noon. Not an issue. My batteries last a long time.

I did the same when I was gigging. Plug in at soundcheck, unplug at load out. Again, I change batteries about twice a year maybe.